The National Trust has unveiled a list of 50 things a child should do before they are eleven-and-three-quarters as part of a campaign to encourage sofa-bound children to take to the outdoors.

The list which, includes activities like skimming stones, building dens and making mud pies, provides a checklist of simple pleasures for under-12s.

The campaign is in response to a report that the trust commissioned, which highlighted how fewer than one in ten children regularly play in wild places compared to almost half a generation ago.

This report also showed that a third had never climbed a tree, one in ten cannot ride a bike, and three times as many are taken to hospital after falling out of bed, as from falling out of a tree.

The trust has also assembled a group of elite rangers who will share their expert tips on enjoying outdoor adventures. They will offer tips on their specialisms over a free weekend when the trust will open up more than 200 of its houses and gardens.

The initiative has been welcomed by The Scout Association whose assistant director, Simon Carter, said that he has noticed "a great thirst for an adventure" amongst pre-teens and teenagers. "Our membership has gone up for seven years in a row," he said.

But Mr Carter added that he had also noticed that parents ask more questions about the activities that their children will be involved in.

"As an organisation, we have seen that parents are more likely to ask questions like, 'are they lighting fires?, are they sleeping in a tent?' I know that parents are concerned. Not in a nasty way, but in a different way from 10 or 15 years ago."

On health and safety culture, Mr Carter said that parents instinctively know that it is not right to be too protective of their children.

"That is why they send young people to a place they know that they can take risks that are managed in a relatively safe environment."

Richard Williams-Jones, a father-of-one who has blogged about being a stay at home dad, said that television and video games are unfairly maligned. "The quality is pretty good," he said. "For children who live in flats in cities the TV is their window out into the world.

But he welcomed the move. "If the National Trust wants to give people ideas, then that is great. There are only so many times you can go to the park to go on the slide before you go out of your mind."

"It is almost more important to encourage the parents to get out," he added. "You can get isolated really easily."